1. Field of the Invention
The invention relates to a coupling device for a foldable frame, more particularly to a coupling device for a foldable frame that can be operated with relative ease.
2. Description of the Related Art
FIGS. 1 to 4 illustrate a conventional coupling device for a foldable frame, such as a baby crib, disclosed in US 2003/0061658. The conventional coupling device includes a pair of elongate rod members 11, each of which has an engaging end portion 110, and a pivot portion 111 connected to the engaging end portion 110. The conventional coupling device interconnects pivotally the pivot portions 111 of the rod members 11 such that the rod members 11 are operable so as to move from an extended position, where the rod members 11 are aligned with each other in a horizontal direction (see FIG. 2), to a folded position, where the rod members 11 are generally parallel to each other and extend in a vertical direction (not shown).
The conventional coupling device includes a hollow coupling seat body 10, a spring-loaded latch unit 2, and an actuating member 3. The coupling seat body 10, which is configured with an accommodating space, has a top side, a bottom open side, and opposite lateral open sides that are connected pivotally and respectively to the pivot portions 111 of the rod members 11 such that the engaging end portion 110 of each rod member 11 extends into the accommodating space in the horizontal direction via a respective one of the lateral open sides when the rod members 11 are in the extended position, as shown in FIG. 2. The latch unit 2, which is mounted movably in the accommodating space of the coupling seat body 10, includes a pair of engaging blocks 20 spaced apart from each other in the horizontal direction. Each engaging block 20 has an upper coupling end portion formed with an engaging groove 200, and a lower pivot end portion opposite to the upper coupling end portion and connected pivotally to the coupling seat body 10 such that each engaging block 20 is rotatable relative to the coupling seat body 10 about a respective pivot axis transverse to the horizontal and vertical directions. Each engaging block 20 is formed with an engaging rib 22 that extends from the lower pivot end portion thereof toward the other engaging block 20. The latch unit 2 is operable from an engaging position, where the engaging grooves 200 of the upper coupling end portions of the engaging blocks 20 engage the engaging end portions 110 of the rod members 11 so as to retain the rod members 11 in the extended position, as shown in FIG. 2, to a releasing position, where the engaging grooves 200 of the upper coupling end portions of the engaging blocks 20 are unable to engage the engaging end portions 110 of the rod members 11 so as to permit movement of the rod members 11 from the extended position to the folded position, as shown in FIG. 4. The latch unit 2 further includes a coiled compression spring 21 interconnecting the upper coupling end portions of the engaging blocks 20 for restoring the latch unit 2 from the releasing position back to the engaging position. The actuating member 3 has an actuating portion 31 that extends into the accommodating space of the coupling seat body 10 via a front slot 101 in the coupling seat body 10, and that is mounted movably on the coupling seat body 10 via mounting pieces 13, 14 so as to be movable relative to the coupling seat body 10 in a transverse direction transverse to the horizontal and vertical directions, and an operating portion 30 connected to the actuating portion 31, disposed in front of the coupling seat body 10, and operable externally of the coupling seat body 10 for moving the actuating portion 31 along the transverse direction toward a rear side of the coupling seat body 10 such that a bevel plate 311 formed on the actuating portion 31 abuts against and drives the engaging ribs 22 on the engaging blocks 20 to move downwardly so as to enable the latch unit 2 to move from the engaging position to the releasing position.
The following are some of the drawbacks of the aforesaid conventional coupling device:
1. Since the engaging ribs 22 on the engaging blocks 20 are driven to move downwardly by the bevel plate 311 as a result of pressing the operating portion 30 of the actuating member 3 for moving the actuating portion 31 toward the rear side of the coupling seat body 10, a relatively greater amount of force is required to be exerted by the user.
2. Since the operating portion 30 of the actuating member 3 is disposed externally of the front side of the coupling seat body 10, accidental operation of the actuating member 3 is likely to occur.
3. Due to the presence of the engaging ribs 22, the mounting pieces 13, 14, and the bevel plate 311 on the actuating portion 31 of the actuating member 3, the conventional coupling device has a relatively complicated configuration.